Thermoplastic tie-rod

Abstract

A tie rod that includes a central section, a first tapered section, and a second tapered section. A thermoplastic tube extends the length of the tie rod. The first tapered section includes a first insert positioned within the thermoplastic tube. The second tapered section includes a second insert positioned within the thermoplastic tube. A channel extends through the tie rod along the central section, the first tapered section, and the second tapered section.

What is claimed is: 
     
       1. A tie rod comprising:
 a thermoplastic tube comprising a first tapered section, a second tapered section, and a central section extending between the first and second tapered sections; 
 a central channel that extends through the first tapered section, the second tapered section, and the central section; 
 a first insert positioned in the thermoplastic tube at the first tapered section and a second insert positioned in the thermoplastic tube at the second tapered section, each of the first and second inserts comprising a length measured between an outermost end and an innermost end, each of the first and second inserts comprising a continuously decreasing taper along the length and radial fins that extend outward along the length and with a height of the radial fins that continuously increases along the length; 
 an entire length of a first external circumferential boundary of the first insert is equal along the length between the outermost end and the innermost end; and 
 an entire length of a second external circumferential boundary of the second insert is equal along the length between the outermost end and the innermost end. 
 
     
     
       2. The tie rod of  claim 1 , wherein the first and second external circumferential boundaries are equal. 
     
     
       3. The tie rod of  claim 1 , wherein each of the first and second inserts comprises:
 a body with an inner surface and an outer surface, the body comprising an outer width that tapers downward from the outermost end to the innermost end; 
 an opening that extends through an interior of the body between the outermost end and the innermost end; and 
 the fins extend radially outward from the outer surface and that are spaced apart around the body, the fins extending radially outward from the body in different directions. 
 
     
     
       4. The tie rod of  claim 3 , wherein the fins comprise the height measured between the outer surface of the body and an outer edge, the height tapering along the body and being largest at the outermost end and smallest at the innermost end. 
     
     
       5. The tie rod of  claim 3 , wherein each of the first and second inserts further comprise a threaded member positioned within the opening at the outermost end, the threaded member comprising a threaded opening having interior threads that are exposed. 
     
     
       6. The tie rod of  claim 3 , further comprising an annular end cap mounted to the outermost end of each of the first and second inserts, the end cap comprising an opening that aligns with the opening. 
     
     
       7. The tie rod of  claim 3 , further comprising channels that extend within each of the first and second inserts, the channels extending between the inner surface and the outer surface. 
     
     
       8. The tie rod of  claim 7 , wherein the thermoplastic tube is attached to each of the first and second inserts and fibers within the tube having a bowed shape at the channels and extend into the channels. 
     
     
       9. The tie rod of  claim 1 , wherein the central section comprises a constant outer width. 
     
     
       10. A method of manufacturing the tie rod of  claim 1 , the method comprising:
 positioning the first and second inserts within first and second ends of the thermoplastic tube; and 
 preventing the thermoplastic tube from wrinkling while forming the first tapered section at the first end of the thermoplastic tube and the second tapered section at the second end of the thermoplastic tube by conforming the thermoplastic tube to the radial fins and tapered bodies of the first and second inserts. 
 
     
     
       11. The method of  claim 10 , further comprising applying a vacuum to an interior of the inserts and sealing the thermoplastic tube against channels that extend through the inserts. 
     
     
       12. The method of  claim 11 , further comprising deforming fibers in the thermoplastic tube into the channels in the inserts. 
     
     
       13. The method of  claim 10 , further comprising aligning openings in each of the first and second inserts with a hollow interior in the thermoplastic tube and forming a channel that extends through the tie rod. 
     
     
       14. The method of  claim 10 , further comprising attaching end caps to outermost ends of each of the inserts and then adhering the thermoplastic tube to the inserts. 
     
     
       15. The method of  claim 10 , further comprising forming a central section along the tie rod between the first and second tapered sections with the central section comprising a constant outer width. 
     
     
       16. A tie rod comprising:
 a first tapered section; 
 a second tapered section; 
 a non-tapered central section positioned between the first and second tapered sections; 
 a thermoplastic tube that extends along the first and second tapered sections and the non-tapered central section; 
 a first insert positioned within the thermoplastic tube at the first tapered section; 
 a second insert positioned within the thermoplastic tube at the second tapered section; 
 each of the first and second inserts comprising a body that continuously tapers between innermost and outermost ends and radial fins with the radial fins extending outward in different directions away from the tapered body and with a height that increases towards the outermost end; and 
 each of the first and second inserts comprising a length measured between the innermost and outermost ends and having an external circumferential boundary that is equal along the length. 
 
     
     
       17. The tie rod of  claim 16 , wherein the first insert is aligned at a first end of the thermoplastic tube and the second insert is aligned at an opposing second end of the thermoplastic tube. 
     
     
       18. The tie rod of  claim 16 , further comprising a channel that extends the length of the tie rod, the channel being formed by openings within each of the first and second inserts and a hollow interior of the thermoplastic tube. 
     
     
       19. The tie rod of  claim 16 , wherein the thermoplastic tube further comprises braided fibers. 
     
     
       20. The tie rod of  claim 16 , wherein the tapered body of each of the first and second inserts comprises an outer width that tapers from the innermost end downward to the outermost end and the height of the radial fins decreases from the outermost end towards the innermost end.